Remove some unused 3 byte vertex attrib types.

These attrib types don't have equivalents in d3d12 and they are not used
so just deleting them.

Change-Id: Iff63525d36e0674847e07a13254f321c27aca7bc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/279864
Commit-Queue: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
6 files changed